Color adjusting apparatus and method for light source

ABSTRACT

Color adjusting apparatus and method for a light source. A reflector of a required color is added to a light source of a scan module, a plating film of the required color is formed on a lens, or the lens is dyed with the required color. Or alternatively, the color of the light source is directly changed into the required color. As a result, the inconsistent intensities for the light in the primary color, red, green and blue output from the charge-coupled device caused by different brightness of the light source, different wavelength transmission of the lens, and different light sensitivity of the charge-coupled device is improved.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the priority benefit of Taiwanapplication serial no. 91105037, filed on Mar. 18, 2002.

BACKGROUND OF INVENTION

[0002] 1. Field of the Invention

[0003] The invention relates in general to a color adjusting apparatusand method for a light source. More particularly, the invention relatesa color adjusting apparatus and method of use for a light source of anoptical scan module.

[0004] 1. Related Art of the Invention

[0005] As image input, operation and processing have caused popularinterest, the scanner becomes a basic accessory for many computer users.Through the scanner, text or graphs in documents, magazines, books orpictures can be scanned and input into a computer for furtherprocessing. The platform scanner is the most common type among variouskinds of scanners. In the platform scanner, the scan module, installedunder a transparent platform, can be pulled back and forth to scan thedocument on the transparent platform. The scan module itself does nothave a driving mechanism, so the driving mechanism such as a motor,gear, and belt are required.

[0006] While using the platform scanner to scan a document, the documenthas to be disposed on the transparent platform and covered with a lid,which presses the document down on the transparent platform.

[0007] The conventional scan module 700 of an optical scanner (referringto FIG. 1) includes a light source 100, a mirror set 400, a lens set 500and an optical detector such as charge-coupled device (CCD) 600. Whileperforming a scan, the light source (such as a light tube) 100 radiateson the document 200 disposed on the light transparent board 300 (whichis the transparent platform). An imaging light 110 is obtained viareflection (where the light source 100 is located underneath the lighttransparent board 300) or transmission (where the light source 100 islocated over the light transparent board 300). The mirror set 400 is anassembly of multiple mirrors 401, 402, 403 and is located along theoptical path of the imaging light 110. The image of the document 200directed to the mirror set 400 is reflected to the lens set 500 thereby.Through the lens set 500, the imaging light 110 of the document 200 isincident and displayed on the charge-coupled device 600.

[0008] The light source 100 of the optical scan module 700 is a veryimportant device for the whole optical system. The light emitted by thelight source 100 generates various intensities according to thefrequency thereof. Through the function of the charge-coupled device600, for example, after inspection of modulation transfer function(MTF), a certain degree of color deviation often results. Therefore,compensation and correction in a firmware for each scan step is requiredto obtain the correct color. This is very costly and time consuming.

[0009] The function of the lens set 500 is to display the imaging light100 on the charge-coupled display 600. That is, the light signalcollected by the lens set 500 is the material source that all thesubsequent devices are processing. Therefore, the correctness of thelight signal is crucial. Generally speaking, as shown in FIG. 2, thelens set 500 is a composite signal lens consisting of a plurality oflenses, for example, the lenses 510, 520 and 530 as shown in FIG. 1 andinstalled in the lens holder 710. Using lenses with different materialsor curvatures, the aberration caused by a single lens is corrected.However, as the wavelength transmission for the lenses 510, 520 and 530is different, inconsistent output intensities in the primary colors red,green and blue of the charge-coupled device 600 results.

[0010] Further, the charge-coupled device 600 comprises thousands ofoptoelectronic diodes (pixels) arranged in straight lines. Eachoptoelectronic diode comprises three detectors to receive the red, greenand blue color light signals, respectively. In the scanning operation,the charge-coupled device 600 outputs analog red, green and blueelectronic signals for the light received in each sequence. Byanalog-to-digital conversion, the converted signals are then transmittedto the subsequent devices for processing. The detectors of thecharge-coupled device 600 do not detect only one single primary colorsignal. Therefore, frequency response of mutual interference betweencolor signals occurs. The light sensitivity of the charge-coupled device600 is degraded due to different light sensitivity generated fordifferent colors, increased scan moving speed of the charge-coupleddevice 600 and decrease of exposure amount. Accordingly, inconsistentoutput intensities for red, green and blue light are generated by thecharge-coupled device 600.

SUMMARY OF INVENTION

[0011] The present invention provides a color adjusting apparatus andmethod. A reflector with a required color is added to a light source ofa scan module. A plating film with the required color is formed on alens. Or alternatively, the light source is directly switched to therequired color. Thus, the inconsistent output intensities for the threeprimary colors, red, green and blue light, of the charge-coupled devicecaused by different brightness of the light source, different wavelengthtransmission of the lens and the different light sensitivities of thecharge-coupled device is improved.

[0012] The color adjusting method provided by the present invention isapplied to an optical scan module. The optical scan module includes atleast a light source, a mirror set, a lens set and an optical detector.The light source is used to radiate a document to obtain an imaginglight. The mirror set is disposed along an optical path of the imaginglight. Thereby, the imaging light is projected to the optical detector.The lens set is located along the optical path between the opticaldetector and the mirror lens set. The color adjusting method includesthe following steps.

[0013] A reflector is provided and allocated at an opposing side of theside where the light source radiates the document. The color of thereflector is selected from red, green or blue. Through the reflector,the intensity of the selected color of the light source is enhanced.

[0014] Alternatively, a light transparent plating film is formed on asurface of the lens by evaporation plating. The light transparentplating film has a color selected from a group consisting of red, greenand blue colors. Therefore, the intensity of the selected color of thelight source is enhanced.

[0015] The lens may also be dyed to have a specific color selected froma group consisting of red, green and blue colors.

[0016] In yet another alternative embodiment, the original light sourcecan be replaced by a color adjusted light source. The color of theadjusted light source can be selected from a group consisting of red,green and blue light sources, such that the intensity of the lightsource with the selected color is enhanced.

[0017] Accordingly, the inconsistent output intensities for the primarycolors red, green and blue of the charge-coupled device can be improved.

[0018] The present invention further provides a color adjustingapparatus for an optical scan module. The optical scan module comprisesat least a light source, a reflection mirror set, a lens set and anoptical detector. The light source is used to radiate a document, so asto obtain an imaging light. The reflection mirror set is located at anoptical path of the imaging light to direct the imaging light incidentonto the optical detector. The lens set is allocated at the optical pathbetween the optical detector and the reflection mirror. The lightadjusting apparatus further comprises a reflector, of which the color isselected from a group consisting of red color, green color and bluecolor.

[0019] Alternatively, the color adjusting apparatus further comprises atransparent plating film formed on a surface of the lens set. The colorof the transparent plating film is selected from a group consisting redcolor, green color and blue color.

[0020] The present invention further provides an optical scan moduleapplicable for scanning a document. The optical scan module comprises atleast a light source, a reflector, a reflection mirror set, a lens setand an optical detector.

[0021] The light source is used to radiate a document, so as to obtainan imaging light. The reflector is allocated at one side opposing theside where the light source radiates the document. The color of thereflector is selected from a group consisting of red color, green colorand blue color, such that the intensity of the selected color isincreased. The reflection mirror set is located on an optical path ofthe imaging light to receive and reflect the imaging light. The lens setis allocated along the optical path to allow the imaging light reflectedfrom the reflection mirror set to pass therethrough. The opticaldetector is allocated along the optical path, so as to receive theimaging light passing through the lens set.

[0022] The lens set comprises at least one lens, on which a transparentplating film is formed by evaporation plating. The color of thetransparent plating film is selected from a group consisting of redcolor, green color and blue color.

[0023] The lens may also be dyed into a color selected from a groupconsisting of red, green and blue colors.

[0024] Alternatively, the light source may have a color selected from agroup consisting of red, green and blue colors.

[0025] Accordingly, the present invention uses a reflector, a lens or alight source with a specific color to improve the performance of thelight source in such specific color. Therefore, the inconsistent outputintensities for any specific colors (such as red, green and blue colors)of the charge-coupled device are improved.

[0026] The present invention directly improves the performance of thelight source in a specific color, so that the step of compensation andcorrection following each scan is avoided to reduce fabrication time andcost.

BRIEF DESCRIPTION OF DRAWINGS

[0027] These, as well as other features of the present invention, willbecome more apparent upon reference to the drawings wherein:

[0028]FIG. 1 is a cross-sectional view of a conventional optical scanmodule;

[0029]FIG. 2 shows a perspective view of a lens set of a conventionaloptical scan module;

[0030]FIG. 3 is a cross-sectional view of an optical scan moduleaccording to the present invention;

[0031]FIGS. 4a and 4 b show the respective and side view of a lightsource of an optical scan module in one embodiment of the presentinvention; and

[0032]FIG. 5 is a side view showing a lens set of an optical scan modulein a second embodiment of the present invention.

DETAILED DESCRIPTION

[0033] First Embodiment

[0034]FIG. 3 shows a cross-sectional view of an optical scan moduleaccording to the present invention. The optical scan module 1700comprises a light source 1100, a reflection mirror set 1400, a lens set1500 and an optical detector, for example, a charge-coupled device (CCD)1600. While performing scan, the light source 1100 radiates a documentdisposed on a transparent board 1300. By reflection (where the lightsource 1100 is located under the transparent board 1300) or projection(where the light source 1100 is located over the transparent board1300), an imaging light 1110 is obtained. The reflection mirror set 1400is assembled by reflection mirrors 1401, 1402 and 1403 located on anoptical path of the imaging light 1110, such that the imaging light 1110is directed to the reflection mirror set 1400. The imaging light 1110 isthen reflected from the reflection mirror set 1400 and transmitted tothe lens set 1500. The lens set 1500 receives and displays the imaginglight 1110 of the document 1200 reflected from the reflection mirror set1400 on the charge-coupled device 1600.

[0035] Referring to FIGS. 4a and 4 b, the respective schematic drawingand the side view of the light source of the optical scan moduleprovided by the present invention is shown. The light source 1100includes at least one lamp tube (two lamp tubes as shown in FIG. 4), forexample. The light source 1100 is mounted in the lamp base 1720 of theoptical scan module 1700. The method of mounting the lamp tubes 1100includes inserting a rubber plug 1900 at two sides of the lamp base1720. To increase the intensity of the light source 1100, a reflector1800 is allocated at a side opposing to the side where the document 1200is radiated by the light source 1100. The light intensity of the lightsource 1100 is thus enhanced by reflection.

[0036] To improve the inconsistent intensities of the red, green andblue color light output of the charge-coupled device 1600, a reflector1800 with a specific color is incorporated. For example, when red lightis found to have insufficient intensity, a red reflector 1800 is used toenhance the output performance of red light. Similarly, when theintensity of the green light is insufficient, the reflector 1800 withgreen color is used to enhance the output performance of green light. Ifthe intensity of the blue light is found insufficient, a blue reflector1800 is applied to enhance the output performance of blue light. Theintensity or brightness of the color is determined and adjusted bytesting result.

[0037] In addition to generating reflected light in the specific colorby the reflector 1800, the method for enhancing the performance of thespecific color of the light source 1100 further comprises directly usinga light source with such specific color. That is, the red light outputintensity of the charge-coupled device 1600 is found insufficient aftera test, a red light source 1100 is used for compensating suchinsufficiency. If the green light output intensity of the charge-coupleddevice 1600 is insufficient, a greed light source 1100 is used.Similarly, when the blue light output intensity is insufficient, a bluelight source 1100 is used.

[0038] Second Embodiment

[0039] Referring to FIG. 5, a side view of a lens set of an optical scanmodule in a second embodiment of the present invention is shown.Similarly, the lens set 1500 includes a single lens format assembled bymultiple lenses (1510, 1520 and 1530 in this embodiment). To improve theinconsistent intensities for red, green and blue lights, a surface 1512of the lens 1510 is coated with a transparent plating film 1540 with aspecific color. The method for forming the transparent plating film 1540includes evaporation plating.

[0040] For example, when it is found that the charge-coupled device 1600has insufficient intensity for red light, a red transparent plating film1540 is formed to enhance the red light output performance of the lightsource. When the green light intensity output from the charge-coupleddevice 1600 is insufficient, a green transparent plating film 1540 isformed. When the blue light intensity of the charge-coupled device 1600is insufficient, a blue transparent plating film 1540 is formed.

[0041] In addition to the plating film, the lens 1510 can also be dyedinto the specific color to enhance output performance of the specificcolor of the light source 1100. If the output of red light of thecharge-coupled device 1600 is insufficient, the lens 1510 is dyed intored color. The output performance of red light for the charge-coupleddevice 1600 can thus be enhanced. If the output of green light of thecharge-coupled device 1600 is insufficient, the lens 1510 is dyed withgreen color, and when the output of blue light of the charge-coupleddevice is insufficient, the lens 1510 is dyed with blue color.

[0042] The above embodiment only incorporates a plating film on onesurface of one lens, or dyes one lens. According to specificrequirement, the plating film can be formed on a part of the surface, orthe whole surface, of the lens. Further, plating films may also beformed on other lenses, or other lenses can also be dyed.

[0043] According to the above embodiment, the light source, reflectorand lens set are modified to improve the inconsistent intensities ofred, green and blue lights. In the above embodiments, three primarylights are used to explain the present invention. It is appreciated thatthe present invention may also be applied to compensation and correctionof other colors for the light source.

[0044] The present thus has at least the following advantages:

[0045] (1) A reflector or a lens in a specific color, or a light sourcewith this specific color is used to improve the performance of light inthis specific color. Therefore, the inconsistence in intensity for lightin different colors output from the charge-coupled device is improved.

[0046] (2) The performance of the light source in specific color isdirectly improved. Therefore, the compensation and correction stepperformed in the firmware after each scan is avoided to save time andcost.

[0047] Other embodiments of the invention will appear to those skilledin the art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the following claims.

1. A color adjusting method for a light source, used for an optical scanmodule which comprises at least a light source, a reflection mirror set,a lens set and an optical detector, wherein the light source is used toradiate a document to obtain an imaging light, the reflection mirror setis disposed on an optical path of the imaging light to project theimaging light onto the optical detector, and the lens set is located onthe optical path between the optical detector and the reflection mirrorset, the method comprising: providing a reflector at an opposing side ofa side where the document is radiated in the optical source, a color ofthe reflector being selected from a group consisting red, green and bluecolors to reflect and enhance intensity of the selected color for thelight source.
 2. A color adjusting method for a light source, used foran optical scan module which comprises at least a light source, areflection mirror set, a lens set and an optical detector, wherein thelight source is used to radiate a document to obtain an imaging light,the reflection mirror set is disposed on an optical path of the imaginglight to project the imaging light onto the optical detector, and thelens set comprises at least one lens and is located on the optical pathbetween the optical detector and the reflection mirror set, the methodcomprising: forming a transparent plating film on a surface of the lens,a color of the transparent plating film being selected from a groupconsisting of red, green and blue colors to reflect and enhanceintensity of the selected color for the light source.
 3. The methodaccording to claim 2, wherein the step of forming the transparentplating film includes evaporation plating process.
 4. A color adjustingmethod for a light source, used for an optical scan module whichcomprises at least a light source, a reflection mirror set, a lens setand an optical detector, wherein the light source is used to radiate adocument to obtain an imaging light, the reflection mirror set isdisposed on an optical path of the imaging light to project the imaginglight onto the optical detector, and the lens set comprises at least onelens and is located on the optical path between the optical detector andthe reflection mirror set, the method comprising: dying the lens into aspecific color selected from a group consisting of red, green and bluecolor, such that intensity of the selected color for the light source isenhanced.
 5. A color adjusting method for a light source, use for anoptical scan module which comprises at least a light source, areflection mirror set, a lens set and an optical detector, wherein thelight source is used to radiate a document to obtain an imaging light,the reflection mirror set is disposed on an optical path of the imaginglight to project the imaging light onto the optical detector, and thelens is located on the optical path between the optical detector and thereflection mirror set, the method comprising: providing an adjustedcolor light source to replace the light source, the adjusted color beingselected from a group consisting of red, green and blue colors toreflect and enhance intensity of the selected color for the lightsource.
 6. A color adjusting apparatus for a light source, used for anoptical scan module which comprises at least a light source, areflection mirror set, a lens set and an optical detector, wherein thelight source is used to radiate a document to obtain an imaging light,the reflection mirror set is located on an optical path of the imaginglight, so that the imaging light is projected to the optical detector,and the lens set is located on the optical path between the opticaldetector and the reflection mirror set, the color adjusting apparatuscomprising: a reflector, located at the light source at one sideopposing to the other side where the document is radiated by the lightsource, the reflector has a color selected from a group of red, greenand blue colors.
 7. A color adjusting apparatus for a light source, usefor an optical scan module which comprises at least a light source, areflection mirror set, a lens set and an optical detector, wherein thelight source is used to radiate a document to obtain an imaging light,the reflection mirror set is located on an optical path of the imaginglight, so that the imaging light is projected to the optical detector,and the lens set comprises at least a lens and is located on the opticalpath between the optical detector and the reflection mirror set, thecolor adjusting apparatus comprising: a transparent plating film, formedon a surface of the lens, wherein a color of the transparent platingfilm is selected from a group of red, green and blue colors.
 8. Anoptical scan module to scan a document, comprising: a light source, toradiate the document to obtain an imaging light; a reflector, installedin the light source at an opposing side of a side where the document isradiated, the reflector has a color selected from a group consisting ofred, green and blue colors to reflect and enhance light source intensityof the selected color; a reflection mirror set, disposed on an opticalpath of the imaging light to receive and reflect the imaging light; alens set, disposed on the optical lens of the imaging light allowing theimaging light reflected from the reflection mirror set passingtherethrough; and an optical detector, disposed on the optical path ofthe imaging light to receive the imaging light passing through the lensset.
 9. An optical scan module to scan a document, comprising: a lightsource, to radiate the document to obtain an imaging light; a reflectionlens set, disposed on an optical path of the imaging light to receivethe imaging light; a lens set, disposed on the optical lens of theimaging light allowing light reflected from the reflection mirror setpassing therethrough, the lens set comprising at least one lens, whereina transparent plating film is formed on a surface of the lens, and thetransparent plating film has a color selected from a group consisting ofred, green and blue colors; and an optical detector, disposed on theoptical path of the imaging light to receive the imaging light passingthrough the lens set.
 10. An optical scan module to scan a document,comprising: a light source, to radiate the document to obtain an imaginglight; a reflection lens set, disposed on an optical path of the imaginglight to receive the imaging light; a lens set, disposed on the opticallens of the imaging light allowing light reflected from the reflectionmirror set passing therethrough, the lens set comprising at least onelens of which a color is selected from a group consisting of red, greenand blue colors; and an optical detector, disposed on the optical pathof the imaging light to receive the imaging light passing through thelens set
 11. An optical scan module to scan a document, comprising: alight source, selected from a group consisting of a red, a green and ablue color light source to radiate the document to obtain an imaginglight; a reflection lens set, disposed on an optical path of the imaginglight to receive the and reflect the imaging light; a lens set, disposedon the optical lens of the imaging light allowing light reflected fromthe reflection mirror set passing therethrough; and an optical detector,disposed on the optical path of the imaging light to receive the imaginglight passing through the lens set